Industry Online Support
Technical Forum
Navigation
difference b/w failsafe(F),fault tolerant(H) and FH module
Created by: deepak.samal05 at: 6/11/2010 4:04 PM (6 Replies)
Rating 
Thanks 2
7 Entries
| 6/11/2010 4:04 PM | |
|
Posts: 65 Rating:
|
what is the basic difference bet working of failsafe(F),fault tolerant(H) and FH modules??? is that difference due to software or the hardware???? |
| 6/11/2010 4:18 PM | |
Joined: 9/27/2006 Last visit: 12/26/2024 Posts: 12316 Rating:
|
Hello deepack; As a quick answer: S7-400F (fault-tolerant) systems are designed as fail-safe CPUs, for SIL2/3 (safety)applications, where process safety and protection of personnel is the most important issue. S7-400H (high-availability)systems are designed for redundant applications, where two CPus share the I/Os and the data so a fault appearing on one of the two doews not bring the control system down. S7-400HF combine both designs. You can find a lot more information in hthis S7-400 Controller webpage from the A&D Mall (look at the available links on the right of the page): https://eb.automation.siemens.com/goos/catalog/Pages/ProductData.aspx?catalogRegion=WW&language=en&nodeid=5000014&tree=CatalogTree®ionUrl=%2f#activetab=product& Hope this helps, Daniel Chartier |
This contribution was helpful to
|
|
| 6/11/2010 4:40 PM | |
|
Posts: 183 Rating:
|
Hello deepck.samal05; ==> F device. Device certified as Failsafe. For example an F CPU is able to have an F program. This program is processed by both processors on CPU: normal processor (Normal program) and Failsafe processor. This assure that an internal hardware failure is detected (it doesn't matter if the failure is in normal or Failsafe processor). An F-I/O module collect data and HF Interface Module communicate with DP Master through special safety frames inside the same Profibus telegram. ==>H device. Device able to be redundant.For example an H system is formed by two H CPUs. ==>F/H device. An H system(two H CPUs) is able to have an F-program in each H-CPU (the same program, actually). So you can have: F system. For example: one H-CPU, one HF IM+ F-modules connected with Profibusto the H- CPU. F/H system. For example: two H-CPUs in H-Rack with optical interface for redundancy connected through redundant profibus to two HF IM+ F-modules. learn more in: http://support.automation.siemens.com/WW/view/en/35016980 |
This contribution was helpful to
|
|
| 6/11/2010 6:21 PM | |
|
Joined: 9/27/2006 Last visit: 12/26/2024 Posts: 12316 Rating:
|
Hello deepak; Safety-related controls are very standardized, and supervised internationally by technical bodies (TÜV, for one): human llives are at stake. You could program some safe E-Stop program of your own design in a S7-300 CPU for example, but you could not claim (or sell it) as a safety program. To do so, you need a Fail-Safe CPU (such as a CPU 315F-2DP), Fail-Safe I/Os and a Fail-Safe program (the software for programming and certification of safety related controls for S7-300 CPUs is Siemens' Distributed Safety package). And the fail-safe program must go through a certification procedure (internal) before it is setup in the workplace. In the F-CPUs, you can have both safe and non-safe programming, safe and non-safe I/Os, all sharing the environment of the S7-CPU. But they are kept apart, and you cannot for example use a standard input to activate a safety function: your processor would go to STOP mode with a fault. For more information, have a look at the Distributed Safety manual, along with a description of safety programming from the preface of the manual: S7-Distributed Safety: http://support.automation.siemens.com/WW/view/en/22099875 Principles of Safety Functions in S7 Distributed Safety Functional safety is implemented principally through safety functions in the software. Safety functions are executed by the S7 Distributed Safety system to place or maintain the system in a safe state in case of a dangerous occurrence. Safety functions are contained mainly in the following components: ● In the safety-related user program (safety program) in the F-CPU ● In the fail-safe inputs and outputs (F-I/O) |
Last edited by: dchartier at: 6/11/2010 6:22 PM |
|
Follow us on